Rio das Ostras weather in May

In May, Rio das Ostras sees average daytime highs of 26°C and overnight lows near 19°C, with 60 mm of rain across 9.5 wet days and about 10.9 hours of daylight. It is the 8th-warmest and 9th-wettest month of the year here.

Day-to-day highs hold fairly steady near 26°C through the month. The sky is clear or mostly clear about 41% of the time in May, and the air most often feels muggy.

Daylight stretches from about 11 h 12 min at the start of May to 10 h 42 min by month's end. Set against the rest of the year, May is Rio das Ostras's 4th-clearest and 10th-windiest month. For the whole year in context, see Rio das Ostras's year-round climate.

Daytime high
26°
8th warmest
Overnight low
19°
5th coldest
Rainfall
60 mm
9.5 wet days
Daylight
10 h 54 min
7:16 AM – 6:12 PM
Cloud cover
50%
4th clearest
Wind
9 km/h
10th windiest
Solar energy
3.8 kWh/m²
Travel score
6.9
out of 10

Rio das Ostras is human settlement in Brazil.

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 26°C through the month.

A typical May day in Rio das Ostras reaches about 26°C in the afternoon and slips back to 19°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 23°C and 30°C. Set against its neighbours, May runs about 2°C cooler than April and on par with June.

15°20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
12720
22720
32720
42720
52720
62720
72720
82720
92720
102720
112619
122619
132619
142619
152619
162619
172619
182619
192619
202619
212619
222619
232619
242619
252619
262619
272619
282619
292619
302618
312618

How May really feels in Rio das Ostras

Once humidity and wind are folded in, May averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

May sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Rio das Ostras weather by month

How May compares with the rest of the year at a glance. May is the 8th-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 23°20616.613.24.1
Feb31° / 24°13612.712.84.2
Mar30° / 23°17217.812.24.3
Apr28° / 21°851211.55.7
May26° / 19°609.510.96.9
Jun26° / 18°315.910.67.6
Jul25° / 18°295.610.87.8
Aug26° / 18°346.311.27.6
Sep26° / 19°7310.111.96.7
Oct27° / 20°1081212.56.1
Nov27° / 21°20317.513.15.1
Dec29° / 23°2221913.44.2

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 41% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 21% of May, with mostly cloudy or overcast conditions the remaining 38%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16634
26634
36634
46634
56634
66535
76535
86436
96337
106238
116040
126040
135941
145941
155842
165842
175842
185842
195842
205842
215842
225941
236040
246139
256238
266238
276337
286535
296535
306535
316733

Chance of precipitation in May

Any precipitation

Rio das Ostras gets around 60 mm of rain over 9.5 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 31% and peaks near 33% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%151015202531
Rain chance (%)
133
233
333
432
532
632
732
832
932
1032
1133
1233
1333
1433
1533
1633
1733
1833
1933
2032
2132
2232
2331
2430
2530
2629
2728
2827
2926
3026
3125

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

Most of May feels muggy — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, May lands in the muggy band about 48% of days. Sticky, muggy-or-worse air turns up on roughly 64% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
103194534
203204631
303214629
404224727
504234726
604244824
704254823
804264822
905274821
1005284820
1105284819
1205294818
1305304817
1405314816
1505314815
1605324914
1705324914
1805334913
1906334912
2006334911
2106345010
2207345010
230734509
240734518
250835508
260835497
270935497
280935496
2901036486
3001036486
3111035486

Wind in May

Winds average 9 km/h in May.

Across May, daily wind ranges from about 9 km/h on the calmest days to 9 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
19calm
29calm
39calm
49calm
59calm
69calm
79calm
89calm
99calm
109calm
119calm
129calm
139calm
149calm
159calm
169calm
179calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm
319calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 11 h 12 min at the start of May to 10 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 30 minutes over May. Sunrise moves from 7:10 AM to 7:23 AM, and sunset from 6:20 PM to 6:07 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.27:106:20
211.27:106:20
311.17:106:19
411.17:116:18
511.17:116:18
611.17:126:17
711.17:126:16
811.17:136:16
911.07:136:15
1011.07:146:15
1111.07:146:14
1211.07:156:14
1311.07:156:13
1411.07:156:13
1510.97:166:12
1610.97:166:12
1710.97:176:11
1810.97:176:11
1910.97:186:10
2010.97:186:10
2110.97:196:10
2210.87:196:09
2310.87:206:09
2410.87:206:09
2510.87:216:08
2610.87:216:08
2710.87:216:08
2810.87:226:08
2910.87:226:08
3010.77:236:07
3110.77:236:07

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 3.8 kWh/m².

For context, solar energy here swings from a low near 3.54 kWh/m² to a high of 6.31 kWh/m² in February across the year — May's 3.8 kWh/m² sits near the bottom.

012345151015202531
Solar energy (kWh/m²)Level
14.2Bright
24.2Bright
34.2Bright
44.2Bright
54.1Bright
64.1Bright
74.0Bright
84.0Bright
94.0Moderate
103.9Moderate
113.9Moderate
123.9Moderate
133.8Moderate
143.8Moderate
153.8Moderate
163.7Moderate
173.7Moderate
183.7Moderate
193.6Moderate
203.6Moderate
213.6Moderate
223.6Moderate
233.6Moderate
243.6Moderate
253.6Moderate
263.6Moderate
273.6Moderate
283.6Moderate
293.6Moderate
303.6Moderate
313.6Moderate
Planning a trip in May

Hazard calendar for Rio das Ostras

In seasonPeak

None of Rio das Ostras's seasonal hazards are active in May. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Rio das Ostras's rainy season runs October–March, when most of the year's rain falls.

Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is May a good time to visit Rio das Ostras?

Our two travel scores rate May for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

6.9
Sightseeing
4th-best month of the year
6.7
Beach & pool
4th-best month of the year

May is a reasonable time to visit Rio das Ostras for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Rio das Ostras in May

From May's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In May, Rio das Ostras sees daytime highs around 26°C and nights near 19°C. Worth packing: light clothes and rain gear. About 10 days see rain.

light clothesrain gear

Sea temperature near Rio das Ostras in May

The nearest coast averages about 24°C in May — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 13 km away) is warmest in March at about 25°C and coldest in September near 21°C.

The water stays above 20°C all year — warm enough for a swim any month.

20°22°24°26°JanFebMarAprMayJunJulAugSepOctNovDeccoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan24Refreshing
Feb24Warm
Mar25Warm
Apr25Warm
May24Refreshing
Jun23Refreshing
Jul22Refreshing
Aug22Refreshing
Sep21Refreshing
Oct22Refreshing
Nov22Refreshing
Dec24Refreshing

UV index in Rio das Ostras in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Rio das Ostras peaks around January 16 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 11 at about 6 (high).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highHighVery highExtremeJan 16UV 14Jul 11UV 6
UV index (midday)Level
Jan14Extreme
Feb14Extreme
Mar13Extreme
Apr9Very high
May7High
Jun6High
Jul6High
Aug8Very high
Sep8Very high
Oct12Extreme
Nov14Extreme
Dec14Extreme
Location & terrain

Where is Rio das Ostras?

Rio das Ostras sits at 22.5°S, 41.9°W, 11 m above sea level, in Brazil. The nearest listed city is Macaé, 23 km away.

Topography around Rio das Ostras

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Rio das Ostras.

Within 3 km, the terrain around Rio das Ostras has only modest variations in elevation — a maximum elevation change of 49 m around an average of 4 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 693 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,215 m.

The land around Rio das Ostras is covered by water (39%) and artificial surfaces (32%) within 3 km, water (45%) and grassland (27%) within 16 km, and water (37%), trees (31%) and grassland (28%) within 80 km.

3 km
49 m
16 km
693 m
80 km
2,215 m
treesgrasslandartificial surfacesbare terrainwaterwetlandmangroves
May weather nearby: Macaé 23 km · Buzios 25 km · Casimiro de Abreu 27 km · São Pedro da Aldeia 38 km · Cabo Frio 41 km · Iguaba Grande 45 km · Silva Jardim 48 km · Arraial do Cabo 50 km

Brazil travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / N
127 / 220 V · 60 Hz
Prices
≈ 46% of US
price level, 2025
GDP per capita
$10,713
2025
Happiness
6.6 / 10
World Happiness, 2025
Safe drinking water
89%
of population, 2024
Homicide rate
19.3
per 100k, 2023
Road deaths
16
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 482
Religion
Roman Catholic 57%Evangelical 27%none 9%other 4%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Rio das Ostras (-22.5269°, -41.945°, elevation 11 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).